MediaStream Image Capture API
source link: https://developer.mozilla.org/en-US/docs/Web/API/MediaStream_Image_Capture_API
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MediaStream Image Capture API
Experimental
This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The MediaStream Image Capture API is an API for capturing images or videos from a photographic device. In addition to capturing data, it also allows you to retrieve information about device capabilities such as image size, red-eye reduction and whether or not there is a flash and what they are currently set to. Conversely, the API allows the capabilities to be configured within the constraints what the device allows.
MediaStream image capture concepts and usage
The process of retrieving an image or video stream happens as described below. The example code is adapted from Chrome's Image Capture examples.
First, get a reference to a device by calling MediaDevices.getUserMedia(). The example below says give me whatever video device is available, though the getUserMedia() method allows more specific capabilities to be requested. This method returns a Promise that resolves with a MediaStream object.
navigator.mediaDevices.getUserMedia({ video: true })
.then(mediaStream => {
// Do something with the stream.
})
Next, isolate the visual part of the media stream. Do this by calling MediaStream.getVideoTracks(). This returns an array of MediaStreamTrack objects. The code below assumes that the first item in the MediaStreamTrack array is the one to use. You can use the properties of the MediaStreamTrack objects to select the one you need.
const track = mediaStream.getVideoTracks()[0];At this point, you might want to configure the device capabilities before capturing an image. You can do this by calling applyConstraints() on the track object before doing anything else.
let zoom = document.querySelector('#zoom');
const capabilities = track.getCapabilities();
// Check whether zoom is supported or not.
if(!capabilities.zoom) {
return;
}
track.applyConstraints({ advanced : [{ zoom: zoom.value }] });
Finally, pass the MediaStreamTrack object to the ImageCapture() constructor. Though a MediaStream holds several types of tracks and provides multiple methods for retrieving them, the ImageCapture constructor will throw a DOMException of type NotSupportedError if MediaStreamTrack.kind is not "video".
let imageCapture = new ImageCapture(track);
Interfaces
ImageCapture
An interface for capturing images from a photographic device referenced through a valid MediaStreamTrack.
PhotoCapabilities
Provides available configuration options for an attached photographic device. Retrieve a PhotoCapabilities object by calling ImageCapture.getPhotoCapabilities().
Specifications
Browser compatibility
ImageCapture
Report problems with this compatibility data on GitHubdesktopmobileChromeEdgeFirefoxInternet ExplorerOperaSafariWebView AndroidChrome AndroidFirefox for AndroidOpera AndroidSafari on iOSSamsung InternetImageCaptureImageCapture() constructorFull support59Full support79No supportNogetPhotoCapabilitiesFull support59Full support79No supportNogetPhotoSettingsFull support61Full support79No supportNograbFrameFull support59Full support79No supportNotakePhotoFull support60Full support79No supportNotrackFull support59Full support79No supportNoLegend
PhotoCapabilities
Report problems with this compatibility data on GitHubdesktopmobileChromeEdgeFirefoxInternet ExplorerOperaSafariWebView AndroidChrome AndroidFirefox for AndroidOpera AndroidSafari on iOSSamsung InternetPhotoCapabilitiesfillLightModeFull support59Full support79Compatibility unknown; please update this.?No supportNoFull support46No supportNoFull support59Full support59Compatibility unknown; please update this.?Full support43No supportNoFull support7.0imageHeightFull support59Full support79Compatibility unknown; please update this.?No supportNoFull support46No supportNoFull support59Full support59Compatibility unknown; please update this.?Full support43No supportNoFull support7.0imageWidthFull support59Full support79Compatibility unknown; please update this.?No supportNoFull support46No supportNoFull support59Full support59Compatibility unknown; please update this.?Full support43No supportNoFull support7.0redEyeReductionFull support59Full support79Compatibility unknown; please update this.?No supportNoFull support46No supportNoFull support59Full support59Compatibility unknown; please update this.?Full support43No supportNoFull support7.0Legend
See also
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